Such an ophthalmic display comprises an optical imager for projecting information, of the image or multimedia type. The optical imager serves to shape the light beams coming from an electronic and optical system for generating light beams from an electronic signal, e.g. a system of the miniature screen, laser diode, or light-emitting diode type, for example. The optical imager directs the light beams towards the eye of the user so as to enable the information content to be viewed.
Such a display can be used for viewing multimedia content from a mobile telephone, from a digital player, from a personal computer, from a games console, or from any other device suitable for delivering multimedia content.
The term “display” is used herein to mean an assembly constituted by the optical imager and the electronic and optical system for generating light beams. The conventional elements of the pair of eyeglasses are known as the frame and the ophthalmic lenses carried by the frame.
U.S. Pat. No. 6,204,974 discloses fastening a display on a frame for eyeglasses.
In a first variant, the display is clipped onto the frame, and more precisely onto one of the branches (temples) of the frame.
That type of fastening thus includes an arrangement for releasably securing the display on the frame, enabling the display to be secured on the wearer's pair of eyeglasses when it is desired to use the display, and enabling it to be separated therefrom when so desired, with the eyeglasses then being used in conventional manner.
Nevertheless, that type of fastening does not make any provision for adjusting the imager to match the characteristics of the wearer, such as pupillary distance, for example, where the purpose of such adjustment is to present the wearer with an image that is complete, i.e. an image having no portion thereof hidden by a vignetting phenomenon.
In a second variant, the display comprises an imager hinged on the associated electronic and optical system for generating light beams. That type of display can likewise be clipped onto a branch of a frame.
Although that type of display does indeed provide a releasable arrangement for securing the display on the frame, and also, by virtue of its hinge, enables the position of the imager to be adjusted as a function of the characteristics of the wearer, it nevertheless suffers from the following problems.
Once secured to the frame, the imager can be positioned correctly relative to the eye of the wearer by moving the hinge. If the imager is subsequently removed, then its non-rigid assembly is very difficult to keep in the same position. In other words, the relative position of the imager and of the electronic and optical system for generating light beams will be modified, so adjustment needs to be performed again each time the imager is put into place.
Furthermore, that hinge assembly is relatively bulky, which is inconvenient after it has been separated and needs to be put away, e.g. in the pocket of a garment, and it is of relatively unattractive appearance when secured to the frame of a pair of eyeglasses.